Take-off configuration

Since it is clearly an advantage for an aircraft to be able to operate from the minimum possible length of runway there is a strong pressure on the designer to have as low a stalling speed as possible. This requirement is not compatible with the demand for low drag at cruise and the section is modified for take-off by means of leading-edge slats, trailing-edge flaps and other devices already mentioned. For light aircraft the runway requirements are generally not too great and a simple trailing-edge flap deflection, or indeed no modification at all, may be sufficient. For high performance aircraft or transonic transport aircraft, however, more sophisticated high lift devices are required (Chapter 3). In par­ticular some sort of leading-edge slat or droop will normally be employed. Figure 13.2 shows a typical take-off configuration.